Field of the Invention
The disclosed and claimed concept relates to forming a cup-shaped body and, more specifically, to providing a rotary valve for use in a cup ejection system.
Background Information
It is known in the container-forming art to form two-piece containers, e.g. cans, in which the walls and bottom of the container are a one-piece cup-shaped body, and the top, or end closure, is a separate piece. After the container is filled, the two pieces are joined and sealed, thereby completing the container. The cup-shaped body typically begins as a flat material, typically metal, either in sheet or coil form. Blanks, i.e., disks, are cut from the sheet stock and then drawn into a cup. That is, by moving the disk through a series of dies while disposed over a ram or punch, the disk is shaped into a cup having a bottom and a depending sidewall. The ram may have a concave end. The device structured to form the cup is identified as a “cupper.” In some cuppers, after the ram and dies separate, the formed cup remains disposed over the ram until ejected therefrom, typically by a jet of air. The cup may be drawn through additional dies to reach a selected length and wall thickness. Cuppers are shown in U.S. Pat. Nos. 4,343,173; 5,628,224; and 6,014,883.
Cuppers may employ an operating mechanism having a single drive shaft coupled to multiple rams, for example, it is known to have multiple rams move essentially simultaneously. Thus, one cycle of the operating mechanism produces multiple cups. It is further known to slightly stagger the impact of the rams on the sheet material and/or dies, by positioning the rams, sheet material and/or dies at slightly different elevations. At the end of the forming cycle, the cups may remain on the end of the rams. The cups may be removed therefrom by a jet of air, or other fluid, that is passed through the ram and into the space between the cup and the concave end of the ram, as shown in U.S. Pat. No. 4,343,173.
Compressed air, or another fluid, is supplied either continuously or intermittently to the ram via a compressed gas system. Each configuration of such compressed gas systems has problems. For example, if the system is structured to provide a continuous supply of compressed gas, much of the gas is wasted. That is, during the drawing of the cup and during most of the time the ram is being retracted, the cup is not free to move from the end of the ram. Thus, gas supplied to the ram during such operations is wasted. Further, the gas must be vented and such venting may be very noisy. Alternatively, the flow of gas may be controlled by one or more valves that open only when a cup is to be ejected. Given that cuppers produce thousands of cups per hour, such valves must also open and close thousands of times an hour leading to wear and tear as well as the need to replace the valves. Further, the opening and closing of the valves requires a control system or a mechanical linkage structured to time the operation of the valve to the position of the ram. Electronic control systems are expensive and mechanical systems are subject to wear and tear.
There is, therefore, a need for a compressed gas system for a copper that uses less gas and is less noisy.